1. Field of the Invention
The present invention relates to an optical fiber end surface polishing apparatus for polishing the end surface of an optical fiber attached to a ferrule. More specifically, the present invention relates to a novel optical fiber end surface polishing apparatus capable of being easily handled by taking the operability of the apparatus into consideration.
2. Description of the Related Art
One of the inventors of the present invention has proposed the optical fiber end surface polishing apparatus disclosed in U.S. Pat. No. 4,979,334. The optical fiber end surface polishing apparatus according to the invention is arranged such that the end surface of a ferrule with an optical fiber is pressed against an elastic polishing device which makes a composite circular motion by turning on its own axis and revolving around some other axis so that the end surface of the ferrule with the optical fiber can be polished and molded to a flat surface, right angle spherical surface or inclined spherical surface. At present, the apparatus is widely used.
In the optical fiber end surface polishing apparatus according to the above patent, a mechanism for applying a polishing force to the end surface of a ferrule with an optical fiber attached to a polishing holder is disposed in relation to a polishing holder mounting shaft. That is, the polishing force applying mechanism adjusts the polishing force of the polishing holder mounting shaft which contains a polishing force adjusting mechanism to a prescribed value, inserts a polishing holder guide shaft into a guide hole formed to the center of the polishing holder, and applies the polishing force through the center of the polishing holder.
A problem arising in an adhesive removing process for removing an adhesive used to adhere an optical fiber to a ferrule will be described with reference to FIG. 12 and FIG. 13. As shown in FIG. 12, in a conventional optical fiber end surface polishing apparatus, a regular polishing force W may be applied to the extreme end of an optical fiber 2 attached to a ferrule 1 in the adhesive removing process which is the first process in polishing as shown in FIG. 13. In such a case, when a polishing film 3 is pressed against the optical fiber 2, an adhesive 4 is exfoliated from the end surface of the ferrule 1. At the time, the extreme end of the optical fiber 2 is irregularly damaged with ease as shown in FIG. 13.
To cope with the above problem, the adhesive removing process is performed with a polishing force in a fraction of the regular polishing force W using a polishing device prepared separately so that the adhesive is manually removed. Further, in the optical fiber end surface polishing apparatus of the embodiment, when it is necessary to adjust a polishing force in order to adjust the radius of curvature of a polishing surface and improve optical quality, a polishing force set once must be adjusted each time the adjustment is required. Thus, a complex adjusting job is necessary to readjust the polishing force of the polishing holder mounting shaft to a prescribed value.
There has been known an optical fiber end surface polishing apparatus of a type employing an air cylinder as another polishing force adjusting means. In such an apparatus, however, attendant devices such as an air compressor, air cleaner, air pressure regulator, air piping and the like and a space where they are installed are necessary. Thus, there is a problem that maintenance and management are made complex as well as a large installation area is required.
In an ordinary ferule with optical fiber polishing process, an optical fiber is polished with a polishing film having a rough mesh first and thereafter sequentially polished with a polishing film having a medium mesh, a polishing film having a fine mesh and finally mirror-finished with a polishing film having ultra-fine abrasive grains. A polishing holder is removed from a polishing device in each polishing process to remove and clean exfoliated abrasive grains and polished chips deposited on the extreme end surface of a ferrule and at the same time the polished surface of the optical fiber is visually checked as a mid-process inspection and then the ferrule is transferred to the polishing job of the next process. Accordingly, the conventional optical fiber end surface polishing apparatus mounts and dismounts the polishing holder 8 times in total.
A main object of the present invention is to provide an optical fiber end surface polishing apparatus for solving the technical problems to improve and enhance the workability of the conventional optical fiber end surface polishing apparatus mentioned above.
Another object of the present invention is to provide an optical fiber end surface polishing device capable of easily mounting and dismounting a polishing holder on and from a polishing holder arm by engaging a key block mounted on the polishing holder arm with the peripheral groove of the polishing holder by rotating the key block forward and rearward 90.degree. as a means for mounting and dismounting the polishing holder on and from the polishing holder arm.
Still another object of the present invention is to provide an optical fiber end surface polishing apparatus having a double polishing force adjusting mechanism for adjusting polishing force double which is composed of a primary polishing force applying device as a primary polishing force applying means, which employs a coil spring disposed above the upper surface of a block member mounted on the upper surface of a base plate, and a pin which is horizontally rotatably disposed to the outer periphery of the primary polishing force applying device and applies a polishing force by being engaged with a secondary polishing force adjusting surface having a plurality of steps.
A further object of the present invention is to provide an optical fiber end surface polishing apparatus which permits a polishing holder arm to rotate and jump upward at least 90.degree. from an approximately horizontal position.
To this end, according to one aspect of the present invention, there is provided an optical fiber end surface polishing apparatus composed of a polishing device surface turning by being supported by a base plate, a holder for supporting a plurality of optical fiber ferrules, a polishing holder arm capable of moving relative to the polishing device surface while supporting the holder and a polishing force applying device for applying a pressure for making the ferrules to come into contact with the polishing device surface under pressure through the polishing holder arm, wherein the polishing holder arm includes a polishing holder mounting/dismounting device having a base section supported by the base plate through a horizontally rotational shaft to permit the device to rotate and move upward from an approximately horizontal position and the other end section engaged with the polishing holder, the holder includes a coupling section whose rotation is restricted by the polishing holder arm and which is detachably coupled with the polishing holder mounting/dismounting device at a center, and the polishing force applying device includes polishing force applying means which moves between a position where it applies a downward spring urging force to the polishing holder arm and a position where it permits the polishing holder arm to rotate and move upward.
The polishing holder is composed of a stepped disc member having a cylindrical section formed at the center thereof, adapters disposed on the same radius of the thin outside edge section formed to the stepped disc member for attaching the plurality of optical fiber ferrules thereto, an U-shaped mounting/guiding groove formed longitudinally to the interior of the cylindrical section and a peripheral groove formed to the interior of the cylindrical section at angles to an axis and communicating with the mounting/guiding groove.
The polishing holder arm includes the polishing holder mounting/dismounting device which can be jumped upward and rotated at least 90.degree. from the approximately horizontal position through the horizontally rotational shaft disposed to an end of a rectangular member mounted on the base plate and detachably mount the polishing holder thereon through the rotational key at the other end thereof which is engaged and disengaged with and from the peripheral grove of the polishing holder.
The polishing force applying device includes a block member mounted on the upper surface of the base plate and having a vertical stepped hole and a vertical screw hole formed coaxially to the upper surface of the block member, a polishing force adjusting knob having a rod disposed to the axial center thereof and engaged with the screw hole, a rotatable nut having a polishing force applying pin horizontally disposed to the outside diameter surface thereof and capable of rotating horizontally and a compressed coil spring interposed between the polishing force adjusting knob and the rotational nut and the assembly of these components is attached to the stepped hole and the screw hole.
The polishing force applying device is arranged such that a mounting/guiding groove and a horizontally rotating shaft hole are formed to the polishing holder arm, the polishing holder arm is attached to the mounting/guiding groove as well as the polishing force applying pin is engaged with any one of a plurality of steps on the adjusting surface formed on the upper surface of the polishing holder arm.